map.put(three, four);
    Iterator<?> i = map.entrySet().iterator();
    i.next();
    i.remove();
    assertNotified(listener, three, four, RemovalCause.EXPLICIT);

    map.put(four, five);
    i = map.keySet().iterator();
    i.next();
    i.remove();
    assertNotified(listener, four, five, RemovalCause.EXPLICIT);

    map.put(five, six);

    i.next();
    i.remove();
    assertNotified(listener, three, four, RemovalCause.EXPLICIT);

    map.put(four, five);
    i = map.keySet().iterator();
    i.next();
    i.remove();
    assertNotified(listener, four, five, RemovalCause.EXPLICIT);

    map.put(five, six);
    i = map.values().iterator();
    i.next();
    i.remove();
    assertNotified(listener, five, six, RemovalCause.EXPLICIT);

oh! she knows such a very little!  Besides, SHE'S she, and I'm I,
and--oh dear, how puzzling it all is!  I'll try if I know all the
things I used to know.  Let me see:  four times five is twelve,
and four times six is thirteen, and four times seven is--oh dear!
I shall never get to twenty at that rate!  However, the
Multiplication Table doesn't signify:  let's try Geography.